Currently, there are no published efficient large scale production methods for the formation of rivastigimine. Prior art methods are thermodynamically inefficient or economically inconvenient.
Processes for manufacturing the drug substance rivastigmine ([3-[(1S)-1-dimethylaminoethyl]-phenyl]-N-ethyl-N-methylcarbamate marketed as Exelon®) and (S)-3-(1-Dimethylamino-ethyl)-phenol are known from WO 98/42643 and WO 2005/058804, which are incorporated herein by reference. However, as discussed above these processes are inefficient on larger scales. The drug substance rivastigimine is currently used for the treatment of Alzheimer's disease and there is a need to improve on existing inefficient production methods.
It is an object of at least one aspect of the present invention to obviate or at least mitigate one or more of the aforementioned problems.
It is a further object of at least one aspect of the present invention to provide an improved process for the manufacture of (S)-3-(1-Dimethylamino-ethyl)-phenol.
It is a yet further object of at least one aspect of the present invention to provide an improved process for the manufacture of rivastigimine and its salts.